To ensure bandwidth required for development of mobile services, base stations are deployed increasingly densely. Bandwidth required by backhaul increases continuously, and Backhaul capacity expansion cannot keep pace with a growth speed of mobile traffic. Backhaul capabilities become a critical bottleneck that constrains development of mobile broadband. As pressure of an operating expense increases gradually and bandwidth pressure occurs due to development of data services, Backhaul data transmission becomes a hot issue that an operator is most concerned with.
To implement site capacity expansion and optimize Backhaul transmission, physical capacity expansion may be performed on a Backhaul to increase transmission resources. However, the physical capacity expansion causes a cost rise. Therefore, compression of data transmitted on a Backhaul becomes a preferred method for optimizing a wireless transmission system.
In an existing radio network protocol stack, two data compression mechanisms are available.
(1) A Packet Data Convergence Protocol (PDCP, Packet Data Convergence Protocol) layer in a radio interface protocol structure provides “header compression” for an Internet Protocol (IP, Internet Protocol) data stream transmitted at an upper layer of the PDCP layer. For example, headers of the following protocols in the IP data stream are compressed: the Transmission Control Protocol/Internet Protocol (TCP/IP, Transmission Control Protocol/Internet Protocol), or Real-time Transport Protocol (RTP, Real-time Transport Protocol)/User Datagram Protocol (UDP, User Datagram Protocol)/Internet Protocol (IP, Internet Protocol). Header compression algorithms mentioned in the TS 25.323 standard include an IP header compression (IP Header Compression) algorithm and a robust header compression (ROHC, Robust Header Compression) algorithm.
(2) A user data application layer provides data compression, which depends on configuration of the application layer itself.
During a process of implementing the present invention, inventors of the present invention find that: in method (1), the PDCP layer can provide data compression for an IP data stream only, that is, only a user data protocol header is compressed, where a good effect is achieved when a payload (Payload) is small, but a compression effect is limited when a Payload is large; for method (2), data compression is not configured for all data application layers.
In conclusion, the foregoing two data compression methods are both targeted at data of a single user, and their compression effects depend on a service type (for example, a Payload size and configuration of an application layer). An overall effect of data compression is limited. Therefore, how to improve compression of data transmitted on a Backhaul to increase throughput of the Backhaul becomes a difficulty discussed in the industry.